Heat a small pan over medium and add 1 tbsp sesame oil. Add 1 tbsp Japanese leek (naganegi) and 3 cloves garlic finely diced and fry until fragrant. Be careful not to let them burn.
Add 1 tbsp sake and 1 tbsp mirin to the pan and mix well.
Add ¼ tsp chili powder and 2 tbsp yellow miso paste (awase) while mixing continuously. Once thickened, remove from the heat.
Divide 440 g cooked Japanese short-grain rice into equal portions of approximately 110g per rice ball. Sprinkle a rice ball mold with a few pinches of salt and then add half of a portion of rice, Press a dent into the middle and add about 1/2 tbsp of the miso mixture.
Add the other half of the rice, sprinkle with a pinch of salt and press the lid on top to finish shaping. Alternatively, shape by hand making sure to wet your hands before handling the rice to prevent sticking and sprinkle your palms with salt to season the outside. (See in post for more detailed instructions on hand-shaping.)